Block the number. For a smart phone you can install a free call blocking app. For a land line you can buy and install an electronic device that blocks calls.
For a simple cell phone ask your carrier. Or put the pest in your contacts list and give them the ring tone "no ring" or "silence". That will send the call to voice mail without ringing.
There was a message for someone who does not live here offering a program to consolidate student loans. It might be on the level, but also could be a collection agency using bait to contact debtors. Who knows.
Somewhere you might have accidentally clicked something that gave these jerks authorization to call you, if you give permission at all they can call even if you're on the national do not call list.
They called me this afternoon and numerous times before today. These calls are bots, but do their best to not seem like it. Mine constantly calls about fake Student Loans, which again, ARE scams.